GB/T 9403-1988

This standard specifies the structure, dimensions, and optical density levels of a reflection grayscale test chart used for evaluating the tone reproduction and contrast response of imaging systems. It is primarily applied in the telecommunications and broadcasting industries for testing and calibrating facsimile machines, document scanners, and other optical transmission equipment that rely on reflected light to capture grayscale images. The chart serves as a reference target to ensure consistent image quality and accurate signal processing during device manufacturing and performance verification.